##############################################
# Analysis of Longitudinal Data (SuSe 2017)  #
#                                            #
# Code to use for tutorial 4                 #  
# Datum: 20.06.2017                          #
##############################################

##############
# Exercise 3 #
##############

## 1e)
# load rats data
library(nlme)
load("rats.long.RData")
str(rats.long)

# Transformation of TIME:
rats.long$logT     <- log(1+(rats.long$TIME-45)/10) 

# take out NAs
rats.long          <- rats.long[complete.cases(rats.long),]

# fit linear model 
lm1 <- lm(RESPONSE ~ GROUP * logT - GROUP, data = rats.long)